1. Field of the Invention
The present invention relates to a mobile track working machine for tamping and ballasting a railroad track, which comprises a first machine frame, a second machine frame, an articulated coupling connecting the machine frames, undercarriages supporting the machine frame on the railroad track for movement in an operating direction, the first machine frame supporting a vertically adjustable ballast tamping unit and a track lifting and lining unit preceding the ballast tamping unit in the operating direction, and the second machine frame supporting a plow for ballasting the track and a ballast broom.
2. Description of the Prior Art
A machine of this type has been disclosed, for example, in U.S. Pat. No. 5,101,733. The ballast broom is mounted at the rear of the machine, with respect to the operating direction, and delivers the swept excess ballast to a preceding conveyor band which conveys the ballast to a ballast tamping unit where it may be discharged in the range of the tamping tools. A ballast plow precedes the ballast broom in the operating direction to enable the ballast bed to be suitably shaped after the track has been corrected and tamped, as the machine advances.
U.S. Pat. No. 4,165,694 also discloses a mobile track tamping and ballasting machine, the ballast plow being mounted in front and a ballast broom being arranged in the rear of the machine for sweeping ballast off the ties. A trailer carrying the ballast plow is connected to the machine frame carrying ballast tamping units by a longitudinally adjustable drive so that the trailer may advance continuously while the track is tamped. This track leveling, lining and tamping machine attempted to solve the problem of combining the different technologies involved in the step-by-step tamping operation and the continuous plowing operation.
European Patent No. 397,956 describes a continuously (non-stop) advancing track working machine for tamping and ballasting a railroad track, which comprises three machine frames connected to each other by articulated couplings. The plow and broom positioning is similar to that of U.S. Pat. No. 4,165,694.